The goal of the proposed research is to understand the process of intracellular proteolysis in bacteria. Already available peptidase mutants of Salmonella typhimurium and Escherichia coli will be further characterized and new types will be obtained. The important peptidases and proteases will be purified and characterized biochemically. The effects of peptidase and protease mutations on protein modification and maturation and on protein degradation will be studied. BIBLIOGRAPHIC REFERENCES: Genetic mapping of Salmonella typhimurium peptidase mutations. Miller, Charles G. J. Bacteriol. 122, 171-176, 1975. Peptidases and proteases of Escherichia coli and Salmonella typhimurium. Miller, Charles G. Ann. Rev. Microbiology 29, 485-504, 1975.